stereo/speakers issue, only highs work

[bleu7]

Hello and thanks for looking, I was wondering if I could have some insight.into what may be my issue, my speakers will at random stop working and only push out the highs and only highs at very low volume and then randomly the speakers go back to normal.

ive been told my speakers are going out but if thats the case how come.at times they sound perfect?

I have an aftermarket sony stereo, and it was working fine for about a year and recently its been acting up, any help and input is greatly appreciated.